In this study, we aimed to develop a novel directional electromagnetic field (EMF) application method for promoting plant growth using a solenoid coil-based cultivation system. The emergence of plant shoots from seeds, shoot elongation, root proliferation, and plant growth hormones were monitored in the presence of a directional EMF using our solenoid coil system. To observe the effect of the directional EMF on seed germination, radish and sugarcane seedlings were cultivated in the system. At the seed germination stage, the EMF applied had no significant effect on germination or growth. However, after germination, shoot growth was sensitive to a directional EMF, as it was promoted by different conditions in a plant-species-dependent manner. The maximum growth promotion rates were 25.65% ± 4.21% and 38.57% ± 12.81% for radish and sugarcane, respectively. Similarly, plant root proliferation and indole-3-acetic acid (IAA) analyses indicated that directional EMF application was associated with root proliferation and hormone synthesis. Plant growth in the experimental system proved controllable; either growth stimulation or reduction were possible as the system operating conditions were made to vary. Our findings indicate that the application of a specific directional EMF could serve as an electrical plant stimulant (or electrical fertilizer).

Ho-Hyeong Yang, Hyung-Joo Kim, Sung-Won Bang, Heun-Woo Cho, Hyeong-Seok Lee, Seung-Won Han, Kwang-Jin Kim, and Ho-Hyun Kim. J Environ Health Sci. 2023;49:295-304. https://doi.org/10.5668/JEHS.2023.49.6.295

A method for particulate matter and airborne microorganisms removals using indoor plants with electrical ground connection was investigated. The electrochemically activated plants through electrical grounding were used as the basis of air purification system. In this study, a novel concept of plants-based indoor air purification system was examined in the presence of electrical ground connection. Epipremnum aureum was selected as a primary experimental plant. The cultivation pots with an electrode were connected to earth point via a wire. Experiments were conducted in a system where the pots were placed, with various concentrations of particulate matter and airborne microorganisms were applied to analyze removal rates. In addition, the effects of airflow speed and light conditions on the removal rates were also analyzed. The results demonstrated that applying electrical grounding to indoor plants significantly improved the particulate matter and airborne microorganisms removal rates. In the case of particulate matter removal, the grounded systems showed 75.7 ± 5.5% removal rate under air flow rate of 1.0m/s. Additionally, long-term experiments demonstrated that the grounded system maintained a stable particulate matter removal efficiency of over 60% for 35 days. Regarding airborne microorganisms removal, the grounded system achieved a removal efficiency of 63.3% ± 0.8% for airborne bacteria and 67.6% ± 1.6% for airborne fungi. This study confirmed that applying electrical grounding to indoor plants can significantly enhance their air purification performance. These results suggest that a simple grounding technique applied to potted plants can be an eco-friendly and effective solution for improving indoor air quality.

This study investigated the microbial contamination and community composition on door handle surfaces in public buildings with high pedestrian traffic Door handles from four buildings (A, B, C, and D) were sampled at both the indoor and outdoor sides of the main entrances and restrooms. By evaluating microbial contamination and community composition, this study aimed to provide an objective assessment of hygiene conditions in public facilities and to offer foundational data for improving public hygiene management. Microbial activity was assessed by measuring ATP (Adenosine triphosphate)-based RLU (Relative Light Units). Microbial concentration and community distribution were evaluated through CFU (Colony Forming Unit) counts and DGGE (Denaturing Gradient Gel Electrophoresis) in two buildings (A and B) where pedestrian flow remained stable during the observation period. The sample showing the highest DGGE band diversity was further analyzed using 16S rRNA amplicon sequencing–based metagenomics to determine detailed microbial community composition. The results showed that buildings with higher pedestrian flow exhibited increased surface contamination. For example, Building D recorded the highest foot traffic (192.3±3.1 people h⁻¹), while the restroom door in Building A exhibited the highest ATP level (1,411.7±789.6 RLU) on the indoor handle. Microbial concentrations also varied between indoor- and indoor handle surfaces, depending on both contact frequency and building environmental factors—such as lighting and ventilation. DGGE analysis revealed distinct differences in microbial community structure among the samples, while metagenomics indicated the presence of potentially pathogenic bacteria in the samples. Overall, this study confirms that microorganisms on door handles are influenced by pedestrian traffic, touch frequency, and environmental conditions. These findings underscore the importance of regular cleaning and disinfection of frequently touched surfaces and suggest that implementing non-contact door-opening systems could reduce cross-contamination and improve hygiene in public indoor environments.

Background and objective: While companion plant (also referred to as pet plants) culture has expanded rapidly in South Korea, understanding of the emotional and cultural significance of companion plants remains limited. This study aimed to promote emotional engagement with plants and foster the development of companion plant culture through the “2025 Companion Plant Poetry and Art Contest.” Using text mining techniques, it analyzed participants’ emotional perception patterns and linguistic expressions toward companion plants based on their contest submissionsMethods: Participant characteristics and contest entries were analyzed according to participation category (Younger Adult Division and Middle-Aged/Older Adult Division) and literary genre (poetry and prose). For text mining analysis, the collected texts were processed using the Okt morphological analyzer in the KoNLPy library. After filtering out non-informative words, key nouns and adjectives were extracted and analyzed according to participation category and literary genre. Additionally, log2 ratio analysis was performed to identify distinctive word usage patterns across participation categories, and the results were visualized using word clouds.Results: Participants perceived a total of 126 plant species as companion plants, with indoor plants accounting for the largest proportion. Text mining analysis showed that participants in both divisions perceived companion plants as “small beings that share emotions.”. In terms of noun use, the Younger Adult Division was characterized by expressions related to growth and daily life, while the Middle-Aged/Older Adult Division showed more retrospective and place-oriented linguistic tendencies. Regarding adjective use, the Younger Adult Division tended to describe using direct sensory expressions, while the Middle-Aged/Older Adult Division more frequently employed expressions evoking visual and spatial imagery.Conclusion: These results suggest that distinct linguistic characteristics emerged across participation categories. The Younger Adult Division tended to perceive companion plants through themes of growth, care, and daily life, whereas the Middle-Aged/Older Adult Division expressed companion plants through memories, spaces, and seasonal reflection. These findings provide insights into generation-specific characteristics of emotional perception and expression toward companion plants, contributing to a broader understanding of companion plant culture.

This study evaluated the feasibility of a small-scale system for recovering moisture from indoor air and reusing the recovered water for indoor plant irrigation. A condensate production system comprising a thermoelectric module, cooling plate, and heat sink was developed and integrated into a plant pot. By lowering the cooling surface temperature to the dew point or below, the system condensed and collected moisture from the surrounding air. During the plant cultivation experiment, 66 paired observations of dew point temperature and condensate production were obtained, with a mean condensate production of 35.38 ± 18.44 mL day⁻¹. Physicochemical water-quality analysis was conducted to characterize the collected condensate. To assess its suitability for irrigation, a cultivation trial was conducted using Humata tyermannii, Hedera helix, and Hoya carnosa ‘Exotica Hort’. After Holm correction for multiple comparisons, most growth parameters did not differ significantly between the condensate and tap water treatments, whereas root fresh weight was significantly higher in the condensate treatment for H. tyermannii and H. helix. A supplemental energy test conducted in 2026 showed an overall specific energy consumption of 23.27 kWh L⁻¹ under the tested conditions, indicating that energy efficiency remains an important limitation of the current experimental system. These findings support the feasibility of condensate reuse for indoor plant irrigation under the tested conditions and provide baseline data for the development of a proof-of-concept model for circular water use in small indoor green spaces. However, improvements in energy efficiency and further long-term water-quality evaluation are required for practical application.